If you’re a frequent flyer of JetBlue, you may be wondering how to upgrade to Mint, the airline’s premium cabin. Mint is JetBlue’s version of a business class experience, offering more legroom, larger seats, and a variety of amenities. Here’s How to upgrade to Mint JetBlue. Book your flight. When you book your flight, you’ll have the option to upgrade to Mint. You can do this online or by calling the customer service team at US Number: OTA: +1-800-971-7347 or +1-800-538-2583.